AMERICAN 
JOURNAL OF BOTANY 
Vol. VII July, 1920 No. 7 
MEASUREMENT OF THE CATALYTIC POWER OF CATALASE 
L. G. M. Baas Becking and H. C. Hampton 
I. Introduction 
In this paper we propose to describe a new method and a new principle 
of determining the strength of catalase action. We do not endeavor to 
sum up all the literature existing, the excellent works of C. Oppenheimer^ 
and H. Euler^ having made this unnecessary. Of the literature which has 
appeared since 1909 we have taken only such work into account as showed 
an immediate connection with ours. Therefore we merely mention the 
elaborate work of G. B. Reed.^ 
The present problem originated from a proposed research on autofer- 
mentation in Cannabis sativa L. The first enzym to be dealt with was 
catalase. There were many difficulties to be overcome before we could 
start the work. The easiest way is to take commercial peroxide and let it 
act on crude plant juice, determining either the oxygen discharged by the 
method described by H. H. BunzeH or the peroxide decomposed by means 
of titration with permanganate of potassium — the latter the method of 
nearly all other authors. With both methods we made determinations, 
but were very soon convinced that we were not ascertaining the actual 
strength of the enzym. One aim of the present paper, therefore, is to 
attempt to prove the inadequacy of the existing methods. 
The value of a new method depends entirely on three factors: (i) The 
purity of the enzym; (2) the purity of the peroxide; and (3) the way of 
determining the action of the enzym on the peroxide. We took care only 
of the third factor in our experiments, though for the sake of completeness 
we mention all three. The first factor may vary according to the different 
aims of the research. 
For studies in kinetics (R. O. Hertzog^), the enzym must be free from 
crystalloid, from peroxidase, and from impurities. For physiological 
research the methods of precipitation, be it with strong alcohol, inorganic 
salts or lead acetate, or by dialysis and centrifuging, enfeeble the enzym to 
1 Die Fermente, Zehnte Aufl Leipzig, 1909. 
2 Grundlagen und Ergebnisse der Pflanzenchemie, 2ter Teil. 1909. 
^ Bot. Gaz. 1915-1918. 
^ Journ. Biol. Chem. 20. 1914. 
^ Zeitschr. Physik. Chem. 41. 1904; Oppenheimer, Part IL 
[The Journal for June (7:223-260) was issued July 29, 1920.] 
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